With increasing requirements for wireless network capacity, to obtain higher network capacity, sites are deployed more densely. For a Long Term Evolution (LTE) system, regardless of a homogeneous network (HomNet) or a heterogeneous network (HetNet), because sites are deployed more densely, interference between cells is more severe. As a result, a throughput of users on a border of the cells decreases, and the normal work of edge users is affected in a severe case. Staggering resources of the edge users can resolve the interference problem between the cells. The conventional method is using inter-cell time domain interference coordination. With the help of coordination of the use of subframes between different cells, staggering of interference between the cells is implemented. This is specifically implemented by using an almost blank subframes (ABS) technology. An ABS subframe sends no data at all, and transmits only a reference signal. Some subframes for an interfering cell are set as ABS subframes, and an interfered-with cell is hardly interfered with in the corresponding subframes.
A prerequisite of implementing the inter-cell time domain interference coordination is time synchronization between cells. A general method is performing the time synchronization between the cells by using a global positioning system (GPS), which requires that GPS be configured for each site. The GPS-based synchronization technology is referred to as a hard synchronization technology. Performing the time synchronization by using the GPS has problems of high construction costs and high maintenance costs.